Shell slender, elongate-ovate, velvety shining, height 22.0 mm, width 10.1 mm. Planktotrophic protoconch with 3.5 transparent whorls; the last keeled. Holotype's protoconch is incomplete. Teleoconch with 5.5 slightly convex whorls, first 3 finely ribbed and showing 4 to 6 fine spiral grooves. The rest of the whorls smooth, except a fine spiral groove below the suture and microscopic growth lines. Suture narrowly ledged.
Last whorl with 7 to 8 spiral grooves at the base and approximately 7 low ribs near outer lip. Outer lip with 4 to 5 denticles and approximately 15 evenly sized lirae inside, not variced and with a narrow edge of callus. Aperture oval. Columellar callus thick, marginated and narrow, following the aperture from the siphon to the anal canal, anteriorly 2 to 3 pustules. Parietal denticle strong. Anal canal prominent. Siphonal area with 6 to 7 grooves.
Shell white, scattered with brown, body whorl on dorsal side reddish-brown, darker near suture, lighter near outer lip with 2 faint bands. Aperture, outer lip and columellar callus white. Operculum (in paratype) yellowish, serrated.
After photography the protoconch and the anterior part of the outer lip of the holotype have been damaged.
Intraspecific variation: There is a rather great difference in color. Dead-collected shells lose the brown color and become white, which hinders an accurate identification. Size of adult specimens varies from 15.1 to 25.5 mm.

Some of the lots used here to describe N. velvetosus sp. nov. have already been mentioned by Cernohorsky (1991: 200), who misidentified them with Nassarius comptus (A. Adams, 1852). Specimens resembling N. comptus are frequently misidentified. However, the lectotype of N. comptus shows strongly ribbed early whorls, whereas N. velvetosus sp. nov. has many fine ribs on the first 3 teleoconch whorls and is considerably more slender.
Cernohorsky (1991: 200) also misidentified another lot of N. velvetosus sp. nov. under the name Nassarius haldemanni (Dunker, 1847). Dunker (1847: 62) described the species with the name "Buccinum haldemani" with a single 'n', evidently after the American malacologist Samuel Haldeman (1812-1880), although no etymology was given. The spelling Nassarius haldemanniy frequently used in literature, is a misspelling. The holotype of N. haldemanni figured by Cernohorsky (1984: 283, Fig. 10), is considerably smaller in size (up to 14 mm) and has a smooth, carinated protoconch of 3 whorls; protoconch and first teleoconch whorl brownish.
A third resembling species is Nassarius tangaroai Kool, 2006, which is smaller in size and has fewer and stronger ribs on the first apical whorls. It is known only from the Marquesas Archipelago.

Nassarius velvetosus sp. nov. lives between 24-302 m from Vanuatu to New Caledonia. The occurrence in Fiji has to be confirmed with better quality additional specimens. Type locality
Vanuatu, South Urelapa Island, 15°37'S, 167°02'E, 116 m